U.S. patent number 11,446,442 [Application Number 16/637,793] was granted by the patent office on 2022-09-20 for gasket and syringe having the same.
This patent grant is currently assigned to COKI ENGINEERING INC.. The grantee listed for this patent is Coki Engineering Inc.. Invention is credited to Akira Yotsutsuji.
United States Patent |
11,446,442 |
Yotsutsuji |
September 20, 2022 |
Gasket and syringe having the same
Abstract
A gasket suitable for a syringe stopping with vacuum is
provided. The gasket is compatible with sliding property within the
sleeve and water-tightness of the syringe barrel after exiting the
sleeve. The gasket includes a gasket body made of a
liquid-resistant hard plastic having a tip surface contacting
medicinal solution and a concave groove formed on a side surface
facing an inner peripheral surface of a syringe barrel and formed
continuously to the tip surface contacting medicinal solution; and
a sliding contact ring made of an elastic material fitted in the
concave groove. Then, an outer diameter D1 of a peripheral end of a
tip portion including the tip surface contacting medicinal solution
of the gasket body is set to be larger than the outer diameter D4
of the sliding contact ring.
Inventors: |
Yotsutsuji; Akira (Osaka,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Coki Engineering Inc. |
Osaka |
N/A |
JP |
|
|
Assignee: |
COKI ENGINEERING INC. (Osaka,
JP)
|
Family
ID: |
1000006569044 |
Appl.
No.: |
16/637,793 |
Filed: |
August 29, 2017 |
PCT
Filed: |
August 29, 2017 |
PCT No.: |
PCT/JP2017/030922 |
371(c)(1),(2),(4) Date: |
February 10, 2020 |
PCT
Pub. No.: |
WO2019/043784 |
PCT
Pub. Date: |
March 07, 2019 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20200215269 A1 |
Jul 9, 2020 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M
5/31513 (20130101); A61M 5/3129 (20130101); A61M
5/31515 (20130101); A61M 2205/0222 (20130101); A61M
2005/3131 (20130101); A61M 2205/0238 (20130101); A61M
5/31511 (20130101); A61M 2005/3104 (20130101) |
Current International
Class: |
A61M
5/315 (20060101); A61M 5/31 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
|
201586295 |
|
Sep 1999 |
|
CN |
|
2494683 |
|
Mar 2013 |
|
GB |
|
H11-47275 |
|
Feb 1999 |
|
JP |
|
2009505794 |
|
Feb 2009 |
|
JP |
|
5406416 |
|
Feb 2014 |
|
JP |
|
1999/044659 |
|
Sep 1999 |
|
WO |
|
2007027585 |
|
Mar 2007 |
|
WO |
|
2009001600 |
|
Dec 2008 |
|
WO |
|
2016/113409 |
|
Jul 2016 |
|
WO |
|
Other References
CNIPA, Office Action for corresponding Chinese Patent Application
No. 201780094153.9, dated May 28, 2021, with English translation.
cited by applicant .
International Search Report dated Oct. 17, 2017 for Application No.
PCT/JP2017/030922 and English translation. cited by applicant .
KIPO, Office Action for corresponding Korean Patent Application No.
10-2020-7004979, dated Dec. 6, 2021, with English translation.
cited by applicant .
EPO, Extended European Search Report for corresponding European
Patent Application No. 17922951.3, dated May 18, 2020. cited by
applicant .
First Examination Report of corresponding Indian Patent Application
No. 202027008993 dated Mar. 7, 2022, with English translation.
cited by applicant .
CNIPA, Office Action for corresponding Chinese Patent Application
No. 201780094153.9, dated Dec. 10, 2021, with English translation.
cited by applicant.
|
Primary Examiner: Osinski; Bradley J
Attorney, Agent or Firm: Lucas & Mercanti, LLP
Claims
What is claimed is:
1. A gasket, comprising: a gasket body made of a medicinal
solution-resistant hard plastic and having a tip surface configured
for contacting medicinal solution and a concave groove formed on a
side surface configured for facing an inner peripheral surface of a
syringe barrel and formed continuously to the tip surface
configured for contacting medicinal solution; and a sliding contact
ring made of an elastic material fitted in the concave groove,
wherein an outer diameter of a peripheral end of a leading portion
of the gasket body including the tip surface configured for
contacting medicinal solution is larger than an outer diameter of
the sliding contact ring, in a state of being fitted into the
syringe barrel, a peripheral edge portion of the tip surface
configured for contacting medicinal solution of the gasket body
contacts against an inner peripheral surface of the syringe barrel,
and the peripheral edge portion of the tip surface configured for
contacting medicinal solution contacts the inner peripheral surface
of the syringe barrel on a surface of the peripheral edge portion
elongated by being bent in a state that the gasket body is fitted
in the syringe barrel.
2. The gasket according to claim 1, wherein the gasket body is
formed by a cold forming.
3. The gasket according to claim 1, wherein a material of the
gasket body is PTFE, and the elastic material of the sliding
contact ring is silicone rubber to which sliding property is
added.
4. A syringe comprising: the gasket according to claim 1; medicinal
solution; a syringe barrel; and a piston rod.
Description
CROSS REFERENCE TO RELATED APPLICATION
This Application is a 371 of PCT/JP2017/030922 filed on Aug. 29,
2017, which is incorporated herein by reference.
TECHNICAL FIELD
The present invention relates to a gasket suitable for a "syringe
vacuum plugging method using a sleeve" and to a syringe having the
same.
BACKGROUND OF THE INVENTION
For example, the Patent Document 1, Japanese Patent Application
Laid-Open Publication No. 2009-505794, shows a gasket having high
safety and sealing property over a long period of time in a state
where medicinal solution is injected. And the gasket has low
sliding resistance against to a syringe barrel.
The gasket (i.e. plunger tip) for the syringe disclosed in the
Patent Document 1 has a gasket body (i.e. core) in which a concave
groove is formed on a side peripheral surface facing an inner
peripheral surface of the syringe barrel, and a sliding contact
ring (i.e. raised portion) fitted in the concave groove.
In addition, by using material hardly affecting quality of the
medicinal solution for the gasket body that comes into direct
contact with the medicinal solution, and by selectively using
material having high slide ability with respect to the syringe
barrel for the sliding ring, it is possible to obtain slide ability
capable of pushing the gasket with light force while minimizing the
influence on the quality of the medicinal solution.
CITATIONS LIST
Patent Document 1: JP 2009-505794T Patent Document 2: JP
H11-47275A
SUMMARY OF THE INVENTION
However, the conventional gasket described above also has other
problems. That is, the gasket may not be suitable for the syringe
vacuum plugging method using a sleeve. The syringe vacuum plugging
method using a sleeve is described in, for example, Patent Document
2: Japanese Patent Application Laid-Open No. H11-47275.
The "syringe vacuum plugging method using a sleeve" will be briefly
described. The syringe vacuum plugging method using a sleeve is
conducted by inserting a gasket into a metal cylindrical sleeve in
advance, and inserting one end of the sleeve from above into a
syringe barrel into which medicinal solution has been injected in
advance in a vacuum state of a predetermined degree. The sleeve is
then raised relative to the syringe barrel and the gasket so that
the gasket exiting the sleeve remains within the syringe barrel. At
this time, by the elasticity of the gasket itself, the side surface
of the gasket body and the sliding contact ring constituting the
gasket are in close contact with an inner peripheral surface of the
syringe barrel, thereby sealing the medicinal solution. The
manufacture of the syringe has been completed.
In relation to the "syringe vacuum plugging method using a sleeve"
conducted by such a flow, at least an outer diameter of one end
portion of the sleeve needs to be formed smaller than the inner
diameter of the open end portion of the syringe barrel. Therefore,
the gasket is radially compressed in the one end portion of the
sleeve having the smallest diameter until it comes out of the one
end portion of the sleeve. And the gasket comes into close contact
with the inner peripheral surface of the syringe barrel. Then the
gasket slides in the sleeve under a predetermined pressing force
even under this compression. After the gasket comes out of the
sleeve, the gasket is required to expand by its own elasticity and
seal (water-tight) the inside of the syringe barrel.
As described above, the gasket disclosed in Patent Document 1 keeps
water-tightness by contacting the sliding contact ring of the
gasket to the inner peripheral surface of the syringe barrel.
Furthermore, the outer diameter of the sliding contact ring in a
natural state is formed to be larger than the outer diameter of the
gasket body mainly for the purpose of ensuring the slide ability
and water-tightness of the gasket in the syringe barrel. The
natural state means a state in which the gasket is not fitted in
the sleeve or the syringe barrel.
In general, the thickness of the sliding contact ring is smaller
than the thickness of the gasket body. The thickness of the sliding
contact ring means the distance between the outer end and the
opposing inner end in the radial direction of the sliding contact
ring. And the thickness of the gasket body means the distance from
the center to the outer end in the radial direction of the gasket
body. Therefore, the restoring property of the sliding contact ring
is smaller than the restoring property of the gasket body. The
restoring property means the degree of returning to the dimension
before compression when it is expanded again by its own elasticity
after being compressed to a predetermined dimension.
Therefore, when a conventional gasket is applied to the "syringe
vacuum plugging method using a sleeve", if the outer diameter of
the sliding contact ring in the natural state is set so that the
gasket slides within the sleeve with a predetermined pressing
force, there is a possibility that a problem that the
water-tightness of the syringe barrel after the gasket is pulled
out of the sleeve arises. And conversely, if the outer diameter of
the sliding contact ring is set large to such an extent that no
water-tightness problem of the syringe arises, there is a
possibility that a problem that the gasket does not slide easily
within the sleeve arises.
The present invention has been developed in view of the problems of
the prior art. It is therefore a principal object of the present
invention to provide a gasket suitable for the "syringe vacuum
plugging method using a sleeve" which is compatible with sliding
within the sleeve and with the water-tightness of the syringe
barrel after the gasket has been pulled out from the sleeve.
According to an aspect of the present invention,
A gasket comprises:
a gasket body made of a medicinal solution-resistant hard plastic
and having a tip surface contacting medicinal solution and a
concave groove formed on a side surface facing an inner peripheral
surface of a syringe barrel and formed continuously to the tip
surface contacting medicinal solution; and
a sliding contact ring made of an elastic material fitted in the
concave groove,
wherein an outer diameter of a peripheral end of a leading portion
of the gasket body including the tip contact liquid surface is
larger than an outer diameter of the sliding contact ring.
Preferably, when the gasket is fitted in the syringe barrel, a
peripheral edge portion of the tip surface contacting medicinal
solution of the gasket body contacts against an inner peripheral
surface of the syringe barrel.
Preferably, the peripheral edge portion of the tip surface
contacting medicinal solution contacts the inner peripheral surface
of the syringe barrel on a surface elongated by being bent the
peripheral edge portion in a state that the gasket body is fitted
in the syringe barrel.
Preferably, the gasket body is formed by the Cold forming.
Preferably, the material of the gasket body is PTFE, and the
material of the sliding contact ring is silicone rubber to which
sliding property is added.
Preferably, the gasket is used for a syringe vacuum plugging method
using a sleeve.
According to another aspect of the present invention,
A syringe includes a gasket as described above is provided.
According to the gasket of the present invention, the outer
diameter of the peripheral end at the tip portion including the tip
surface contacting medicinal solution of the gasket body is set to
be larger than the outer diameter of the sliding contact ring.
Therefore, when the gasket is fitted in the sleeve, the sliding
contact ring is compressed in the radial direction, and the
peripheral end portion of the tip portion of the gasket body is
compressed in the radial direction so as to bend toward the rear
end surface side of the gasket body and slightly cover a tip
portion side of the sliding contact ring. Then, when the gasket is
fitted into the syringe barrel, the outer peripheral surface of the
sliding contact ring and the peripheral edge portion of the tip
surface contacting medicinal solution of the gasket body comes into
contact the inner peripheral surface of the syringe barrel.
As described above, regarding the gasket of the present invention,
the water-tightness of the syringe barrel is ensured by the
peripheral edge portion of the tip surface contacting medicinal
solution of the gasket body contacting on the inner peripheral
surface of the syringe barrel. The restoring property of the gasket
body is greater than the restoring property of the sliding contact
ring. After the diameter of the gasket body and the sliding contact
ring is greatly reduced in the radial direction as the gasket
passes through the sleeve, the gasket body attempts to restore to a
greater degree than the sliding ring. Therefore, the
water-tightness in the syringe barrel is easily ensured when the
gasket is fitted into the syringe barrel having an inner diameter
slightly larger than the outer diameter of the sleeve. The present
invention provides a gasket suitable for the "syringe vacuum
plugging method using a sleeve" which was compatible with both
sliding property within the sleeve and water tightness of the
syringe barrel by the gasket after exiting the sleeve.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view showing the syringe 100 in
accordance with an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing the gasket 10 in
accordance with an embodiment of the present invention.
FIG. 3 is a cross-sectional view showing the gasket body 12 in
accordance with an embodiment of the present invention.
FIG. 4 is a cross-sectional view showing the sliding contact ring
40 in accordance with an embodiment of the present invention.
FIG. 5 is a cross-sectional view of an embodiment of a sleeve 90
for use in the "syringe vacuum plugging method using a sleeve".
FIG. 6 is a cross-sectional view of an embodiment of the gasket 10
fitted in the syringe barrel 60.
FIG. 7 is a cross-sectional view illustrating the syringe vacuum
plugging method using a sleeve using the gasket 10 in accordance
with an embodiment of the present invention.
FIG. 8 is a cross-sectional view showing the syringe 100 completed
with the syringe vacuum plugging method using a sleeve.
FIG. 9 is a cross-sectional view showing the gasket 10 in
accordance with another embodiment.
FIG. 10 is a cross-sectional view showing the gasket 10 in
accordance with yet another embodiment.
FIG. 11 is a cross-sectional view showing the gasket 10 in
accordance with yet another embodiment.
FIG. 12 is a cross-sectional view showing the gasket 10 in
accordance with yet another embodiment.
FIG. 13 is a cross-sectional view showing the sliding contact ring
40 in accordance with another embodiment.
FIG. 14 is a cross-sectional view showing the sliding contact ring
40 in accordance with yet another embodiment.
DETAILED DESCRIPTION OF THE INVENTION
(Structure of a Gasket 10 and a Syringe 100)
A gasket 10 in accordance with an embodiment of the present
invention and a syringe 100 including the gasket 10 will be
described in accordance with the illustrated embodiment.
As shown in FIG. 1, the syringe 100 includes a gasket 10, medicinal
solution 50, a syringe barrel 60, a piston rod 70, and a top cap
80.
As shown in FIG. 2, the gasket 10 includes a gasket body 12 and a
sliding contact ring 40.
As shown in FIG. 3, the gasket body 12 includes a tip end surface
(referred to herein as "a tip surface contacting medicinal solution
14") that comes into contact with the medicinal solution 50 when
the gasket 10 is fitted into the syringe barrel 60. The gasket body
12 also includes a tip portion 16 that is formed in an umbrella
shape and has an outer diameter that increases as it approaches the
rear end side, a small diameter portion 18 that is rapidly reduced
in diameter in a step shape continuing the tip portion 16, and an
enlarged diameter portion 20 that is increased in diameter in a
step shape continuing the small diameter portion 18.
As described above, since the step is formed between the tip
portion 16 and the small diameter portion 18, a trailing end side
of the tip portion 16 has the largest outer diameter and has an
angular shape. In this specification, the trailing end side of the
tip portion 16 having the largest outer diameter is referred to as
a peripheral end 22.
Further, since steps are formed between the tip portion 16 and the
small diameter portion 18 and between the small diameter portion 18
and the enlarged diameter portion 20, a part corresponding to the
small diameter portion 18 becomes a concave groove 26 formed over
the entire circumference of the side surface 24 of the gasket body
12. The step between the tip portion 16 and the small diameter
portion 18 is referred to as a leading side step 33, and the step
between the small diameter portion 18 and the enlarged diameter
portion 20 is referred to as a trailing end side step 34.
Further, the outer diameter D1 of the peripheral end 22 of the tip
portion 16 is formed to be larger than the outer diameter D2 of the
enlarged diameter portion 20. That is, in the gasket body 12, the
outer diameter D1 of the peripheral end 22 is formed to be the
largest.
A screw hole 30 for mounting the piston rod 70 is formed in the
rear end face 28 of the gasket body 12. Further, a ridge portion 32
protruding toward a side direction of the gasket body 12 is formed
on the surface of the enlarged diameter portion 20 over the entire
circumference of the side surface 24 of the enlarged diameter
portion 20. The ridge portion 32 has an outer diameter
substantially equal to or slightly smaller than the inner diameter
of the syringe barrel 60. As a result, the ridge portion 32 serves
as a guide for preventing a central axis of the gasket 10 from
being largely displaced from a central axis of the syringe barrel
60 when the gasket 10 slides within the syringe barrel 60. The
ridge portions 32 may be provided at least three places on the side
surface 24 of the enlarged diameter portion 20, instead of the
entire circumference of the side surface 24 of the enlarged
diameter portion 20. The three ridges 32 are preferably disposed at
equal angles to each other on a plane perpendicular to the central
axis of the gasket body 12. The central axis of the gasket body 12
means that the central axis along the direction of travel through
the syringe barrel 60.
The method of molding the gasket body 12 is not particularly
limited, and may be, for example, cutting using a lathe or the
like, or injection molding. It is preferable to form the gasket
body 12 by the "Cold forming" method as described in "Modification
1" which will be described later.
The gasket body 12 is entirely formed of a hard material (a hard
plastic having chemical resistance) that does not react with the
medicinal solution 50 such as a fluorine resin, PTFE
(polytetrafluoroethylene), PFA
(tetrafluoroethylene-perfluoroalkylvinylether copolymer), FEP (a
copolymer of ethylene tetrafluoride and propylene hexafluoride),
PCTFE (polychlorotrifluoroethylene), PVDF (polyvinylidene
fluoride), PP (polypropylene), ultra-polymer polyethylene, COP
(cycloolefin polymer), or COC (ethylene norbornene copolymer). For
example, the gasket body 12 of the present embodiment is formed of
PTFE.
The hardness of the hard plastic material is preferably 70 or more
in Shore A hardness (or 40 to 100 in Shore D hardness and 40 to 70
in Rockwell M hardness).
The PTFE used in the present embodiment may be pure PTFE. But it is
more preferable to use a modified substance in which 1 to 15% by
weight of a fluorine resin is mixed. The fluorine resin is, for
example, such as a polytetrafluoroethylene-perfluoroalkyl vinyl
ether copolymer (abbreviated as PFA) or a
tetrafluoroethylene-hexafluoropropylene copolymer, which is a
crystallization inhibitor of PTFE. By using the modified substance,
the gasket body 12 obtains elasticity.
A pure PTFE or a modified PTFE can be used for this embodiment.
Further, a closed-cell block (or round bar) formed by a hot
isostatic pressing (HIP) process also be used for this
embodiment.
The primary sintered block of the PTFE is obtained by
compression-molding pure PTFE powder or modified PTFE powder and
sintering the compression-molded powder. In this sintering, the
contact portions between the powders are in close contact with each
other, but very fine gaps are formed in the non-contact portions.
As a whole, the minute fluids are passed through the continuous
fine gaps.
When the primary sintered block of this PTFE is pressed by the hot
isostatic pressing, the primary sintered block of the PTFE is
compressed, and the ultrafine gaps existing between the grains of
the PTFE are reliably closed, and closed cells are formed. Further,
the hot isostatic pressing under reduced pressure is more
effective.
Next, the sliding contact ring 40 will be described. As shown in
FIG. 4, the sliding contact ring 40 is a ring-shaped member having
a rectangular cross-sectional shape. And the inner diameter D3 of
the sliding contact ring 40 is set to be substantially the same
size or slightly smaller than the outer diameter of the small
diameter portion 18 of the gasket body 12. The outer diameter D4 of
the sliding contact ring 40 is set to be smaller than the outer
diameter D1 of the peripheral end 22 of the tip portion 16 of the
gasket body 12 and larger than the outer diameter D2 of the
enlarged diameter portion 20.
The width W1 of the sliding contact ring 40 is set smaller than the
width W2 of the small diameter portion 18 of the gasket body 12.
See FIG. 3. In other words, the width W1 of the sliding contact
ring 40 is set smaller than the width W2 of the concave groove 26
formed on the gasket body 12. Therefore, when the sliding contact
ring 40 is fitted into the concave groove 26, a gap S is formed
between the side surface of the sliding contact ring 40 and at
least one of the steps of the gasket body 12, as shown in FIG.
2.
The shape of the sliding contact ring 40 is not limited to that of
the present embodiment. And the shape of the sliding contact ring
40 may be, for example, a shape in which an outer end corner is
chamfered as shown in FIG. 13(a), or may be an arc-shaped outer
circumferential surface cross-sectional shape in which the central
portion in the width direction has the maximum diameter as shown in
FIG. 13(b). Further, as shown in FIG. 14(a), the outer peripheral
surface of the sliding contact ring 40 may be defined by the
cross-sectional shape of the waveform. And the cross-sectional
shape of the outer peripheral surface of the sliding contact ring
40 may be tapered such that the central portion in the width
direction has the minimum diameter as shown in FIG. 14(b). Further,
as shown in FIG. 14(c), the cross-sectional shape of the outer
peripheral surface of the sliding contact ring 40 may be tapered
such that the central portion in the width direction has the
maximum diameter. In either shape, the maximum outer diameter of
the sliding contact ring 40 is the outer diameter D4.
The sliding contact ring 40 of the present embodiment is formed of
elastic material. Since the gasket 10 of the present embodiment is
used for the syringe 100, it is preferable that the elastic
material forming the sliding contact ring 40 is already approved as
a medical member, and for example, "silicone rubber" to which
sliding property is imparted.
The "silicone rubber" is a thermosetting resin. And
"organopolysiloxane" in a liquid state, a grease state, or a clay
state as a raw material is a material in which a methyl group, a
vinyl group, a phenyl group, or a trifluoropropyl group is
incorporated in a molecule, and each is used when special
characteristics are required. There are several types of "silicone
rubber". In the present embodiment, any of them can be used. Here,
as an example, a peroxide crosslinked silicone rubber is used. This
peroxide crosslinked silicone rubber contains a liquid or grease
"organopolysiloxane" containing a vinyl group. By adding a
necessary filling and a peroxide curing agent, kneading, and curing
to a target molecular weight, the peroxide crosslinked silicone
rubber is formed. Another example is an addition reaction type
silicone rubber. This addition reaction type silicone rubber is
formed by heating and curing two types of clay polysiloxane by a
reaction using platinum, rhodium, or an organic compound of tin as
a catalyst. One type of polysiloxane contains a vinyl group
incorporated in a molecule. The other type of polysiloxane contains
a reactive hydrogen incorporated in a molecular terminal.
The silicone rubber having the sliding property is formed, for
example, by adding a peroxide (or the curing catalyst and the above
two kinds of clay-like polysiloxanes) as a crosslinking agent to a
liquid, grease, or clay-like organosiloxane, adding a predetermined
amount of silicone oil, and kneading with a kneader. In order to
adjust the hardness of the kneaded material, an appropriate amount
(for example, 25%) of fine silica powder is added as necessary. If
necessary, for example, a predetermined amount of ultra high
molecular weight polyethylene fine powder is added.
The polyethylene resin forming the fine particles of the fine
powder is an ultra-high polymer. For example, the average molecular
weight of such ultra-high polymer is 1 million to 3 million or more
and up to 7 million. Such ultra-high molecular weight particles are
not permeable to water and do not adhere to most of things. Because
of its too high molecular weight, the ultra high molecular weight
polyethylene does not melt even at a high temperature. As a result,
the ultra high molecular weight polyethylene retains its spherical
shape even when molded at a high pressure. The surface of the
spherical ultra high molecular weight polyethylene is relatively
smooth, but some irregularities are also observed. The range of the
particle diameter of the spherical ultra high molecular fine
particles contained in the fine powder is 10 to 300 .mu.m. More
preferably, the range of the particle diameter is 20 to 50 .mu.m.
Depending on a grade, an average particle size of 25 .mu.m, 30
.mu.m or other may be used. In the case where the range of the
particle size distribution is wide, the small particle size enters
between the large particle size and fills the gap between the large
particle size. As a result, the fine filling is realized. Regarding
the fine filling, since the fine particles do not have water
permeability, even if a silicone rubber base material or silicone
oil having water permeability is used, the medical slidable
silicone rubber of the present invention as a whole has very low
water permeability.
The silica fine powder is a powder made of silica sand as a raw
material, and most of the silica powder is made of silicon (SiO2).
It is added to the elastic material in order to adjust its
hardness.
A molding method of the sliding contact ring 40 will be described.
The intended sliding contact ring 40 is formed through the thermal
crosslinking after 1 to 10 minutes by heating and pressing a
molding material described above filled into a compression mold
heated to an appropriate temperature. The molding material means
the silicone rubber kneaded by adding silica powder, silicone oil,
and ultra high molecular weight PE powder added as necessary. The
sliding contact ring 40 is preferably subjected to secondary heat
treatment (annealing).
Returning to FIG. 1, the syringe barrel 60 is a cylindrical
container. A mounting portion 66 to which an injection needle (not
shown) is mounted is protruded from the tip of the barrel body 64.
And a flange 68 for finger-hanging is formed at a rear end of the
barrel body 64. As a hard resin, for example, cycloolefin resin
(COP), polypropylene (PP), ethylene norbornene copolymer (COC), or
the like, is used for the material of the syringe barrel 60 in
addition to glass. Since the gasket 10 of the present embodiment
can structurally maintain a high water-tightness of the syringe
barrel 60 as described later, the glass syringe barrel 60 which is
inferior in inner diameter dimensional accuracy to the resin can
also be used.
The piston rod 70 is a rod-shaped member in which a male thread
portion 72 is formed at a tip end portion thereof and a
finger-pushing portion 74 is formed at a rear end portion thereof.
The male thread portion 72 of the piston rod 70 is formed with a
male screw that can be screwed into the screw hole 30 formed in the
gasket body 12 of the gasket 10. A resin such as cyclic polyolefin,
polycarbonate, polypropylene, or the like can be used for the
material of the piston rod 70.
The top cap 80 includes a frusto-conical cap body 82 and a
disk-shaped cap flange 84 extending laterally from the top end of
the cap body 82. The cap body 82 is formed with a recess 86 into
which the mounting portion 66 of the syringe barrel 60 is fitted.
The top cap 80 is formed of an elastomer. A film having chemical
resistance (PTFE or PFA) is laminated on the inner peripheral
surface of the top cap 80. The Elastomer means vulcanized rubber,
thermoset elastomers, thermoplastic elastomers, or the like.
(Procedure for Manufacturing of the Syringe 100)
Next, a procedure for manufacturing the syringe 100 by the syringe
vacuum plugging method using a sleeve using the gasket 10 of the
present embodiment will be explained. The syringe vacuum plugging
method using a sleeve has an advantage in that, unlike a vacuum
plugging injection conducted in a vacuum container, air bubbles do
not easily mix into the medicinal solution 50 at the time of the
plugging, because the plugging can be conducted under the low
vacuum degree.
A sleeve 90 made of metal as shown in FIG. 5 is used for the
syringe vacuum plugging method using a sleeve. In the present
embodiment, the sleeve 90 is made of stainless steel whose surface
and inner surface are mirror-polished. The sleeve 90 includes a
pipe-shaped sleeve body 91 and a sleeve flange 94 extending
laterally on the inlet end side for which the gasket 10 is inserted
into the sleeve body 91. The outer diameter of the sleeve body 91
is formed such that the inlet end side into which the gasket 10 is
inserted is thick, and the outlet end side from which the gasket 10
is out is narrower. The outlet end side will be inserted into the
syringe barrel 60. A part of the inner surface 92 of the sleeve
body 91 is tapered so that the inner diameter of the sleeve body 91
is smaller at the outlet end than at the inlet end.
By the syringe vacuum plugging method using a sleeve, the gasket 10
is fitted into the syringe barrel 60, as shown in FIG. 6. FIG. 6
also shows a state in which the male thread portion 72 of the
piston rod 70 is screwed into the screw hole 30 of the gasket body
12.
As shown in FIG. 7, the gasket 10 is previously fitted into the
sleeve 90 from the inlet end of the sleeve 90 in a state in which
the tip surface contacting medicinal solution 14 is directed toward
the syringe barrel 60 before the syringe vacuum plugging method
using a sleeve. At this time, the gasket body 12 and the sliding
contact ring 40 of the gasket 10 are respectively fitted in the
sleeve 90 in a radially compressed state. As described above, in
the gasket 10 of the present embodiment, the outer diameter D1 of
the peripheral end 22 in the tip portion 16 of the gasket body 12
is set to be larger than the outer diameter D4 of the sliding
contact ring 40. And the outer diameter D4 of the sliding contact
ring 40 is set slightly larger than the inner diameter of the
sleeve 90. As a result, when the gasket 10 is fitted into the
sleeve 90, the sliding contact ring 40 is compressed in the radial
direction, and the peripheral end 22 of the gasket body 12 is
compressed in the radial direction so as to being bent toward the
rear end face 28. And the peripheral end 22 of the gasket body 12
slightly covers the tip portion 16 side of the sliding contact ring
40. That is, the outer peripheral surface of the sliding contact
ring 40 contacts against the inner surface 92 of the sleeve 90, and
the peripheral edge portion 15 of the tip surface contacting
medicinal solution 14 of the gasket body 12 bends toward the rear
end face 28. Thereby the peripheral edge portion 15 contacts
against the inner surface 92 of the sleeve 90.
In this state, the top cap 80 is attached to the mounting portion
66 of the syringe barrel 60 in advance. And the tip end portion of
the sleeve 90 is inserted into the syringe barrel 60 filled with
the medicinal solution 50. Then, the rear end face 28 of the gasket
body 12 is pressed by a rod-shaped member such as a piston keeping
a positional relationship between the syringe barrel 60 and the
gasket body 12 unchanged, and only the sleeve 90 is moved upward
(i.e., in a direction away from the syringe barrel 60). As a
result, the gasket 10 slides within the sleeve 90 while keeping the
positional relationship with the syringe barrel 60. And finally, as
shown in FIG. 8, the gasket 10 comes out of the outlet end of the
sleeve 90. Then the outer peripheral surface of the sliding contact
ring 40 and the peripheral edge portion 15 of the tip surface
contacting medicinal solution 14 of the gasket body 12 contact on
the inner peripheral surface 62 of the syringe barrel 60.
(Features of Gasket 10)
(1)
According to the gasket 10 of the present embodiment, the outer
diameter of the peripheral end 22 of the tip portion 16 of the
gasket body 12 is set to be larger than the outer diameter of the
sliding contact ring 40. As a result, when the gasket 10 is fitted
into the sleeve 90, the sliding contact ring 40 is compressed in
the radial direction. And the peripheral end 22 portion of the
gasket body 12 is compressed in the radial direction so as to being
bent toward the rear end face 28 and cover the corner portion of
the sliding contact ring 40 on the tip portion 16 side. When the
gasket 10 is finally fitted into the syringe barrel 60, the outer
peripheral surface of the sliding contact ring 40 and the
peripheral edge portion 15 of the tip surface contacting medicinal
solution 14 of the gasket body 12 come into contact with the inner
peripheral surface 62 of the syringe barrel 60.
In the case of the gasket 10 of the present embodiment, the
water-tightness of the syringe barrel 60 is ensured by the
peripheral edge portion 15 of the tip surface contacting medicinal
solution 14 of the gasket body 12 that comes into contact with the
inner peripheral surface 62 of the syringe barrel 60. As described
above, since the thickness of the gasket body 12 is larger than the
thickness of the sliding contact ring 40, the restoring property of
the gasket body 12 is larger than the restoring property of the
sliding contact ring 40. Therefore, even if the diameter of the
gasket body 12 and the sliding contact ring 40 is greatly reduced
in the radial direction when passing through the sleeve 90, when
the gasket body 12 enters the syringe barrel 60 having an inner
diameter slightly larger than the outer diameter of the sleeve 90,
the gasket body 12 attempts to restore to a larger size than the
sliding contact ring 40, so that the water-tightness in the syringe
barrel 60 can be easily ensured.
(2)
In addition, when a side surface of a conventional gasket body is
brought into contact with the inner peripheral surface 62 of the
syringe barrel 60 to ensure the water-tightness as in the
conventional gasket, it is necessary to determine the outer
diameter of the side surface of the gasket body in considering with
the restoring property of the dimension after comes out from the
sleeve 90. High accuracy will be required for such a design and
molding. This is because, if the outer diameter of the side surface
of the gasket body after exiting the sleeve 90 is small relative to
the inner diameter of the syringe barrel 60, the water-tightness of
the syringe barrel 60 cannot be ensured. Conversely, if the outer
diameter of the side surface of the gasket body after exiting the
sleeve 90 is made sufficiently large relative to the inner diameter
of the syringe barrel 60, the gasket must be pushed by an excessive
force when the gasket is inserted through the sleeve 90.
In this regard, in the gasket 10 of the present embodiment, since
the outer diameter of the peripheral end 22 of the tip portion 16
of the gasket body 12 is set to be larger than the outer diameter
of the sliding contact ring 40, the gasket body 12 contacts the
inner surface 92 of the sleeve 90 and the inner peripheral surface
62 of the syringe barrel 60 at the peripheral edge portion 15 of
the tip surface contacting medicinal solution 14 by bending the
peripheral end 22 of the tip portion 16 toward the rear end face 28
side of the gasket body 12. At this time, since the sliding contact
ring 40 is disposed on the rear end face 28 side of the peripheral
end 22 of the tip portion 16 and a gap S is formed between the side
surface of the sliding contact ring 40 and at least one step (the
leading side step 33 or the trailing end side step 34) of the
gasket body 12, it is possible to receive the peripheral end 22 of
the gasket body 12 bent to the rear end face 28 side by the sliding
contact ring 40, and it is possible to prevent the peripheral end
22 from being bent to the rear end face 28 side more than
necessary.
As a result, when the gasket 10 is inserted into the sleeve 90, the
gasket 10 fits to the inner diameter of the sleeve 90 by the
relatively large bending of the peripheral end 22. And when the
gasket 10 exits the sleeve 90, and the gasket 10 fits to the inner
peripheral surface 62 of the syringe barrel 60, which is larger
than the inner diameter of the sleeve 90, by the relatively smaller
bending of the peripheral end 22 than when the gasket 10 is
inserted into the sleeve 90.
Further, in the gasket 10 of the present embodiment, as described
above, the peripheral edge portion 15 of the tip surface contacting
medicinal solution 14 of the gasket body 12 contacts on the inner
surface 92 of the sleeve 90 and the inner peripheral surface 62 of
the syringe barrel 60. A surface of the peripheral edge portion 15
elongated by being bent the peripheral end 22 of the gasket body 12
toward the rear end face 28 in a state in which the gasket 10 is
fitted into the syringe barrel 60 contacts on the inner surface 92
of the sleeve 90 and the inner peripheral surface 62 of the syringe
barrel 60. Therefore, the surface having a roughness smaller than
that of before the gasket body 12 is elongated can contacts the
inner surface 92 and the inner peripheral surface 62. As a result,
the water-tightness of the syringe barrel 60 can be ensured with
higher accuracy as compared with the case where the side surface of
the gasket body as in the conventional gasket contacts on the inner
peripheral surface 62 of the syringe barrel 60.
(Modification 1)
The above-described gasket body 12 is preferably molded by the
"Cold forming" method. The "Cold forming" refers to processing and
forming into a desired shape by applying pressure and generated
heat to the base material under a temperature at which the base
material does not melt. The processing and forming are conducted at
a temperature, for example, about 20.degree. C. to 200.degree. C.
when the base material is PTFE.
The gasket body 12 formed by the "Cold forming" has a "memory
effect (re-memory)". The "memory effect (re-memory)" is a
characteristic that the gasket body 12 deformed by an external
force returns to the original shape when heat is applied.
As a result, when the syringe 100 that has been plugged with the
syringe vacuum plugging method using a sleeve by using the gasket
body 12 molded by the "Cold forming" is heated in steam for
sterilization or disinfection, the bent peripheral end 22 attempts
to return to the original shape. The original shape means a state
in which the degree of bending is smaller by the "memory effect
(re-memory)". The state in which the degree of bending is smaller
means the diameter of the peripheral end 22 is larger. The
medicinal solution 50 may be, for example, a "contrast agent". As a
result, the peripheral edge portion 15 of the tip surface
contacting medicinal solution 14 of the gasket body 12 is pressed
more strongly against the inner peripheral surface 62 of the
syringe barrel 60. Then the water-tightness of the syringe barrel
60 is further enhanced.
(Modification 2)
The shape of the gasket body 12 is not limited to the shape of the
above-described embodiment, and may be, for example, as shown in
FIG. 9, such a shape that the gasket body 12 has a conical
protrusion 110 protruding from a substantially central portion of
the tip surface contacting medicinal solution 14. By providing the
protrusion 110 in this manner, when the medicinal solution 50 is
injected into a patient or the like using the syringe 100 in which
the medicinal solution 50 is filled in the syringe barrel 60, the
protrusion 110 enters the inner space of the mounting portion 66 in
the syringe barrel 60. By entering the inner space, it is
preferable in that more medicinal solution 50 can be injected. In
addition, in the shape of the gasket body 12 as shown in FIG. 10,
the tip surface contacting medicinal solution 14 may be formed in a
planar shape.
Further, although the peripheral end 22 of the gasket body 12 in
the above-described embodiment has a cross-sectional shape in which
the tip portion 16 side is gently curved. The shape of the
peripheral end 22 is not limited to this. As shown in FIG. 11, the
peripheral end 22 may have a rectangular cross-sectional shape in
which the tip portion 16 side is also formed in a planar shape.
Further, as shown in FIG. 12, the cross-sectional shape of the
peripheral end 22 may be formed in an arc shape.
Regardless of the shape, in a state in which the gasket 10 is
fitted into the syringe barrel 60, it is preferable that the
surface elongated by being bent the peripheral end 22 toward the
rear end face 28 contacts on the inner surface 92 of the sleeve 90
and the inner peripheral surface 62 of the syringe barrel 60.
The embodiments disclosed herein are to be considered in all
respects as illustrative and not restrictive. The scope of the
present invention is indicated not by the above description but by
the claims, and it is intended to include all modifications within
the meaning and range equivalent to the claims. 10 . . . gasket, 12
. . . gasket body, 14 . . . tip surface contacting medicinal
solution, 15 . . . peripheral edge portion, 16 . . . tip portion,
18 . . . small diameter portion, 20 . . . enlarged diameter
portion, 22 . . . peripheral end, 24 . . . side surface, 26 . . .
concave groove, 28 . . . rear end face, 30 . . . screw hole, 32 . .
. ridge portion, 33 . . . leading side step, 34 . . . trailing end
side step 40 . . . sliding contact ring, 50 . . . medicinal
solution 60 . . . syringe barrel, 62 . . . inner peripheral surface
(of the syringe barrel), 64 . . . barrel body, 66 . . . mounting
portion, 68 . . . flange, 70 . . . piston rod, 72 . . . male thread
portion, 74 . . . finger-pushing portion, 80 . . . top cap, 82 . .
. cap body, 84 . . . cap flange, 86 . . . recess, 90 . . . sleeve,
91 . . . sleeve body, 92 . . . inner surface (of the sleeve), 94 .
. . sleeve flange, 100 . . . syringe, 110 . . . conical protrusion,
S . . . gap
* * * * *